SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '62f8993c03939b141686ca6fcbc3d7587293f5bbf428fd1bf2ea1e8d355f48d6' 
  AND token = '6EoybzVQ1ylK5TSvjMry+blILKVRJlPprJQj3N+ZR7I=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}